Railway-train-control system.



J. C. McDONALD.

RAILWAY TRAIN CONTROL SYSTEM.

APPLICATION 111150 JAN. 18. 1916.

1,205,463. Pa1ented Nov. 21, 1916.

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' $513 4&4 fiim .wtvlaext com: o. menonann," on NEW YORK, N. Y.

RAILWAY-TRAIN-CONTROL SYSTEM.

Specification of Letters Patent.

Application m January 1a, 1916. Serial No. 72,863.

To all whom it may concern Be it known that I, JOHN G. MCDONALD, acitizen of the United States of America, and a resident of New York, inthe county of New York and State of New York, have invented certain newand useful Improve- .ments in Railway-Train-Control Systems, of

which the following is a specification.

My invention relates to improvements in railway train control systemsand particularly to combined train-stopping and speedcontrol systems,and embodies improvements over the system of the same general nature setforth in my a plication for Letters Patent Serial No. 4 ,581, filedAugust 27, 1915. As in my said prior application, I have illustrated myinvention particularly as applied to electric roads wherein the trainsare operated by electric motors d'eriving current from a third rail orother conductor other than the track rails; but it will be apparent thatthe system isv equally applicable to roads whereon the trains areoperated by steam or other motive power other than electricity. In thefollowing description I will generally refer to the 1 conductor fromwhich the trains receive current for motive power, as the thlrd rall,

- and will generally refer to the conductor from which the trainsreceive current for control, as the fourth rail but it will beunderstood that anyother conductors, for

example, over-head trolley wires, may be substituted for what are,strictly speaking, third and fourth rails, without departure from myinvention.

My invention comprises controlling circuits and instruments, the latterbeing, generally, of the nature of relays, and I have illustrated thetrack relay of each block as controlled by track circuits; though otherwell known means for the control of such to provide simple and effectivemeans for positively stopping trains; to prevent entry of trains intoblocks which are already occupied; to maintain proper block intervalsbetween trains with provision permitting,

under exceptional circumstances, (such forexample as the stalling of atrain ahead) the passage of a train into a block already occupied; tomake the system readily a plicable to'existing railways; and general yto make thecircuitsv and apparatus of the system simple and reliable,and to cause such circuits and apparatus to afford ample pro tection.

I will now proceed to describe my invention with reference to theaccompanying drawings, and will then point out the novel features inclaims.

In the drawings: Figure 1 is a diagrammatic view showing circuits andinstruments for one track of a double track railway, the dlrection ofnormal progress along such track being indicated byan arrow. Fig. 2 1s adiagram of train circuits which may be employed in connection withcircuits shown in Fig. 1. Fig. 3 is a view showing Patented Nov. 21,1916. 1

more or less diagrammatically a relative arrangement of the powercircuit conductor or third rail and the signal circuit conductor orfourth rail with the double contacts of the train shoe and associatedparts, the third rail, the fourth rail, and the insulation support forthe third rail being shown in vertical section.

In the embodiment of my invention herein lllustrated and described, atleast one of the two parallel rails of each track is insulated from theground and divided into block sections, such sections being insulatedfrom each other. The length of such track sectionsv will depend upontraffic conditions and may be determined readily bythose skilled in theart. The third rail or propulsion current conductor may be continuous;but the fourth rail or traincontrol circuit conductor is divided intoblock sections, preferably corresponding generally to'the division ofthe track rail into block sections as above described, the sections ofthe fourth rail being not nee essarily, however, absolutely cotermzinuswith the corresponding sections of the track rail.

Referring now to Fig. 1: R and R designate track rails of which R isshown divided into block sections 2, 3, 4, etc. For each'such blocktherev is a corresponding track relay TR, TR, etc. I have notillustrated a track relay for block 2, but it will be understood thatthe same instruments and circuits are provided for each block. For eachblock there is also another relay, commonly termed a line relay, anddesignated by ref erence characters L L etc. (It will be understood thatthe term relay is em ployed herein in a generic sense, as inclusive ofany type of electrically controlled switching means). I have illustratedthe track relays TR and TR, etc., as controlled by track circuits 7 inthe ordinary manner, each of which circuits will be shunted by thewheels and axles of a train present on the corresponding block, so as todeenergize the corresponding track relays TR TR*, etc. T designates thethird rail or propulsioncurrent conductor and T designates the fourthrail or train control conductor. 0 designates a common return conductorfor the train control circuits and S S etc., designate transformers, onefor each block section, sgpplying alternating current for the traincontrol circuits. SX designates the conductor supplying the alternatingcurrent to the primary coils of these transformers.

The line relays L L etc., are time element or delay action relays; thatis to say, a predetermined interval of time is required for the closingof contact by these relays following the energization of their magnets.Such delay action relays are well known, and I do not limit myself tothe use of any particular type of such relay; but as a diagrammaticillustration of the delay action character of these relays I have shownthe armature of each such relay as provided with a controlling dash-potD. It is well known that by means of such a dash-pot employing eitherliquid or air as the impeding medium, the time required for the closingof contact by the relay may be anything desired within reasonablelimits. Each of the relays TR TR, etc., has three independent armaturecontact points a, b, and c, with corresponding fixed contact points.

The circuits will be best understood by describing the operation of thesystem. Suppose a train to enter block 3 from block 2. As soon as thewheels of that train enter block 3, the track circuit controlling relayTR will be shunted, deenergizing the magnet of relay TR and permittingits armature contacts to drop back. Upon the deenergization of relay TRa circuit will be completed from point 8 of common return conductor 0through armature contact a of relay TR and the back contact of thatarmature through conductor -D* and the magnet of line relay L andthence, through conductor C to the c armature of a track relay of ablock ahead (in this case the track relay TB of the second block ahead)and (this block 6 being understood to be clear) through the c armaturecontact of relay TR, and the corresponding; front contact stop, and thearmature contact d of the corresponding relay L and the correspondingrear contact, through the secondary winding 8 of the transformer S toreturn conductor 0 and thence back to starting point 8. By thecompletion of this alternating current circuit the relay L will beenergized (it will be understood that these relays L L etc, arealternating current relays as well as delay action relays) and thereforethe armature of relay L will be attracted; but since this relay L is adelay action relay, a predetermined interval of time will elapsefollowing the energization of the magnet of this relay L, before contactis made with the front contact of that relay L Should the train soentering block 3 proceed through that block at a speed greater than thatfor which delay action relay L has been timed, such train will reach theentrance of block L before'the front contact of relay L has been made;in which case (since the front contact of this relay L controls thesupply of alternating current from secondary s of transformer S tosection T of the fourth raiL) there will be no alternating current onfourth rail section T, and, therefore, by means hereinafter describedthe train will be brought to rest at the entrance of block 4. If,however, the train in block 3 proceeds through that block ata speed notgreater than that for which relay L has been set,

,by the time that train has reached the entrance of block 4 relay L willhave closed its front contact, and thereby alternating current fromsecondary coil 8 of the transformer S will be supplied through the frontcontact of that relay L to the fourth rail section T, thereby permittingthe train to proceed, as hereinafter described with reference to thecircuits and instruments carried by the train. But now suppose that atthe time the train starts to passfrom block 2 into block 3, block 6 isoccupied. In that event, when the first mentioned train starts to enterblock 3, the magnet of track relay TR will be deenergized, and thecircuit of conductor C through the c armature of relay-TR, and the frontcontact correspond- ISO ing to that armature, will be broken;consequently, the magnet of relay L will not be energized upon the entryof the first mentioned train into block 3, and, when the train proceedsthrough block 3 and reaches the entrance of block 4, relay L will nothave closed the alternating current circuit to the fourth rail section T(supposing block 6 still to be occupied, or not to have been vacated fora time corresponding to that to which relay Lthas been set) andtherefore the train seeking to enter block 4 from block 3 will bebrought to rest by the means hereinafter described.

When the first mentioned train passes from block 2 into block 3, themagnet of relay L will, in general, already have beenenergized and thealternating circuit from secondary s of transformer S will havestruction indicated is a practical one.

will be understood that the train control been applied to fourth railsection T 8 through the front contact of relay L simi= TR will maintainthe circuit through the magnet of relay L*such provision being necessarysince, when the train passes completely out of block 3 the magnet ofrelay TR will be energized and its armature contacts held in attractedposition. When the train has passed completely out of block 4 the magnetof relay TR"= will be energized inturn, its armature contact oints heldin attracted position, and, therefore, the magnet of relay Lwill bedenergized.

It will be seen that by the expedient of extending backward the circuitof each line relay L L etc., to a contact of a. track relaycorresponding to a preceding block, I

obtain a control of the speed of the train passing through thatpreceding block; for should the train exceed the predetermined speed itwill be arrested upon entry into the block to which the particular linerelay under consideration belongs.

As indicated particularly in Fig. 3, the train control conductor T maybe supported from, though insulated from, the propulsion currentconductor T; and the main train contact shoes MS may carry train controlcircuit shoes SS arranged to contact with the train control conductorT;shoes MS and SS being of course, insulated one from another. I havenot attempted in Fig. 3 to show the actual construction of the contactshoes, but have merely indicated the same diagrammatically; though theconconductor T is not necessarily mounted upon the third rail T, asindicated in Fig. 3, but may be supported in any other suitable manner.7

Referring now to Fig. 2: In the case of most electrically propelled carsused where automatic signal systems, and, particularly, automatic trainstopping systems are desired, the running of the car is: co ntro]ledsupply of current to the motors of that car by a circuit such asrepresentedin'part in Fig. 2 by conductors SB and SB"; 'lhis'isparticularly. true in the case of cars ope'rated according to the wellknown multiple unit system; whereby motor controllersgof all the cars ofa train may be opor the supply of current to the motors of any othercarof the train. The circuit SB SB may be understood as representing,diagrzfmmatically, the entire ordinary control system of the car ortrain. I have not shown any source of current for this circuit SB SB,but it will be understood of course that a suitable source of currentsupply is provided for that circuit, as in ordinary practice. It willfurther be understood that, in order that the car or train may proceed,this circuit S13 SB must be closed. For holding this circuit closed, sofar as my present train control system is concerned, a relay GB isprovided, the armature GB of which maybe raised (usually by hand) toclose Contact between terminals of the conductorsSB and SB". This relayGB is, in practice, a cut-out relay, the magnet of which does not havesufficient power to raise the armature CB, when that armature is down,but does have power to hold that armature CB elevated once that armaturehas been raised by hand or otherwise, until the circuit through themagnet of the relay is broken. 12 designates the air brake line of thecar and V a valve in this line, connected to the armature GB in suchmanner that that armature, when in elevated position, holds the valve V-closed (the air brake systm being understood to be of that type whereinthe brakes are set by the opening One or more switches X and Y arelocated at suitable points, usually points from which .thecar or trainis to be controlled. In the drawings these switches are shown in thenormal or non-running position. To each such switch is connected abrake-line valve, V or V, which is normally closed. Other switches A andB controlling valves V and V which are normally open, will be referredto hereafter.

Suppose that the car or train is to be operated from the point at whichswitch X is located. The operator first actuates switch X so as to opencontact A of switch X and to close contact A of switch X, therebyopening valve V He then raises the armature CB, thereby closing valve Vand clos ing circuit SB SB so far as the apparatus shown in Fig. 2 isconcerned.

Train control current may be understood to be received through one orthe other of gized its armature is held in attracted po-- sition andcircuit closed between the termione of the shoes SS and the stop relayGB to one of the main shoes MS and thence to third rail T be opened (andsuch circuit may be opened, as previously explained, by one of the delayaction relays L relay CB will be de'e'nergized and its armature CB willfall, opening the air brake line valve V, which line will then find ventthrough valves V and V so bringing the train to rest. With the parts inthis position, the train may nevertheless be permitted to proceed if theoperator closes the switch A which clggesa, circuit from conductor SBthrough conductor SB switch A conductor S13 contact B of switch Y, toconductor S13 this circuit bridgin the gap between the contacts of relayB due to the dropping of the armature of that relay.

From the above description it will be ap-, parent that trains passingover the track are under automatic control to the extent that not onlywill a train be stopped if it enters a block section-two sections behinda block section already occupied, but also if it passes through. a blocksection at a higher speed than that for which the delay action relay (Letc.,) of the block "section next ahead has been set; the stopping ofthe train in either such case being due to the failure of theappropriate delay action relay to complete the circuit of the secondarys of the corresponding transformer through the fourth rail, shoes SS,the coils of relay CB, shoes MS andthe third rail T. Never theless atrain so stopped will be permitted to proceed if an emergency switchsuch as A or B be closed. I

In my said prior application Serial No. 47,581, I have disclosed asystem. wherein alternating current is used for train control and directcurrent is used for train propulsion, or vice versa, both currentspassing through the third rail, condensers and indu'ctance bonds beingprovided to isolate the direct current circuits from the alternating.current circuits, and-vice versa.

By the present invention, and by such simple means as the employment ofa light fourth rail, conveniently carried by the third rail, I avoidoccasion for the use of such isolating means as the condensers andinductance bonds ofmy said prior application, with consequent greatsimplification. Also, according to my present invention the return forthe alternating current circuits, employed for train control is notthrough the wheels and axles ofthe car and the track rails, andtherefore the voltage in the track circuits may be kept small. Thedropping of a crow-bar or like conductor across either the track railsor across the third and fourth rails can do nothing more than cause thestoppage of a train; it cannot cause the blowing of fuses etc.

Current for the track circuits controlling relays TR and TR, etc., maybe supplied in any suitable manner; Ivhave indicated for this purposeadditional sections a of the transformers, connected to the track rails,as in my said prior application.

Owing to the complete independence of the propulsion circuit and thetrain control circuit, it is not necessary as in my said priorapplication that one of these circuits be an alternating current circuitand the other a direct current circuit; both circuits may be of the samecharacter and, essentially, either may bedirect current circuits, andboth may be direct current circuits if preferred, or both may bealternating current circuits if preferred.

What I claim is 1. A railway train control system comprising apropulsion current conductor and a train control circuit conductor,insulated one from another and the latter divided into sections, incombination with a train circuit connected on one side to the traincontrol conductor and on the .other side to the propulsion currentconductor and including train control means, and means for supplyingtrain control current to said train control conductor and propulsioncurrent "conductor as parts of the train control circuit.

2. A railway train control system comprising a propulsion currentconductor and I control conductor and on the other side to thepropulsion current conductor, and including a train control relay andmeans for supplying train control current to said train controlconductor and propulsion current conductor, as parts of the traincontrol circuit.

3. A railway train control system comprising a propulsion currentconductor and a train control circuit conductor, insulated one fromanother, and thelat'ter divided into sections, in combination with atrain circuit connected on one side to the train control conductor andon the other side to the propulsion current conductor, including a traincontrol relay and means for supplying train control current to saidtrain control conductor and propulsion current conductor, as parts ofthe train control circuit, and a brake line' comprising means operatedby said relay forapplying the brakes.

4. A railway train control system comprising in combination a propulsionourrent conductor and a train control circuit conductor, the latterdivided into sections, means for supplying train control current to saidtwo conductors as opposite sides of a train control circuit, and atime-element device controlling such supply of current,

two contact members, one for one of such conductors and the other forthe other of said conductors, and train control means included in suchtrain circuit.

6. A railway train control system comprising track rails one of which isdivided into block sections, a propulsion current conductor and a traincontrol circuit conductor, extending along the track and in proximity tosaid track rails, the train control circuit conductor divided into blocksections, track circuits passing through such track ,rails and switchesoperated thereby, means for the supply of train con-. trol current tosaid propulsion current conductor and train control circuit conductor asopposite sides of a train control circuit,

, delay action means operated by said switches and controlling thesupply of train control current to said conductors, in combination witha train circuit connected on one side to the train control conductor,and on the other side to the propulsion current conductor, and traincontrol means included in said circuit, the train control circuit beingentirely independent of the track rails.

7. A railway train control system comprising in combination a track,"two 0011- ductors extending along said track, one of said conductorsbeing divided into block sections, means for the supply of train controlcurrent to said conductors as opposite sides of a train control circuit,a time element circuit controller controlling such supply of current,and train actuated means for each block, each such train actuated meanscontrolling the said time element circuit controller of its own blockand the said time element circuit controller of a block in advance.

8. A railway train control system comprising in combination a track, twoconductors extending along said track, one of said conductors beingdivided into block sections, means forthe supply of train controlcurrent to said conductors as oppositevsides of a train control circuit,a time element circuit controller'controlling such supply of current andtrain actuated means for each block, each such train actuated meanscontrolling the said time element circuit controller of its own blockand the said time element circuit controller of a block in advance andthe said time element circuit controller of a block in rear.

9. A railway train control system comprising "in combination a track,two conductors extending along said track, one of said conductors beingdivided into block sections, means for the supply of train controlcurrent to said conductors as opposite sides of a train control'circuit,a time element circuit controller controlling such supply of current,and train actuated means for each block, each such train actuated meanscontrollin the said time element circuit controller of its own block andthe said time element circuit controller of a block in advance and thesaid time element circuit controller of a block in rear, the timeelement circuit controller of each block also controlling the timeelement circuit controller of a block in the rear.

Intestimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

, JOHN o. McDONALD.

Witnesses:

H. M. -MA'RBER,

D. A. DAvms.

